I, too, am a little reticent when it comes to meeting new people, particularly when I know absolutely no one in the crowd. This is exactly the position I was in when I attended my first guild meeting last July. Officially, they welcomed guests, but few introduced themselves or made conversation with me that first meeting.
I joined right away, because I wanted to take advantage of the monthly classes they offered. Jumping right in to take the classes has made it a little easier to become acquainted with the other members. Each one becomes more comfortable.
Hang in there, it does get easier.